my mom was first diagnosed with breast cancer in spring of 2001 and it reappeared spring of 2009. I have a HUGE fear of getting breast cancer but she's one of 14 kids and no one else has had cancer in the family so that gives me a good outlook.
Anyhow mammograms never caught her breast cancer she had them yearly and always noticed her own lumps and would call attention to it. so i think there's no harm in doing a self examination for them and most insurances cover it for your doctor to perform one during your self examination.
They also say women with a family history should take their mothers age, minus 10 years and at that age they should get a yearly mammogram performed. Before then there should be no need. But like i said just be proactive and check yourself, after all we know our bodies best of all?
Inshallah you never get breast cancer, I can understand the worries you may have.